Improvement in the manufacture of steel



W. GERHARDT.

Manufacture of Steel.

No. 40,470. Pg'ented Nov. 3. 1863.

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UNITED STATES PATENT OEETCE.

WILLIAM GERHARDT, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFAGTURE OF STEEL.

Specification forming part of Letters Patent No. 40,470, dated November 3, 1863.

To all lwhom 'it may concern.-

Be it known that I, WILLIAM GERHARDT, of the city, county, and State of New York, have invented a new and useful Improvement in the Manufacture of Steel; and I do hereby declare that the following is a full, clear, and exact description of the same.

The. object and nature of my invention consists in the manufacture of steel from the first product of a blast-furnace in connection with manufactured wrought-iron heated to a white heat in a Crucible or any other reservoir suitable for the purpose, so that by the addition of the pig metal to the before-mentioned highlyheated wroughtiron, to which a proportioned quantity of the oxides of iron or manganese is introduced, in order to increase the heat as well as to decarbonize the diiused cast-iron by the oxygen of the before-mentioned oxides, by their union a fine homogeneous steel will be produced.

`The advantages of my invention are manifold. I will only mention a few of the most important. As without losing the :first heat of the pig-iron cast-steel of line and uniform quality and in large quantity can be produced, and this ata costnot exceeding that of wroughtiron, the importance of this invention must at once strike the eye of those familiar with the present high pricesof good cast-steel, and, considering the difficulties attending to the now so much recommended converting processesas Bessemer and others-all of which require expensive arrangement, it must become selfevident that by applying my process in the manner here below fully specified steel of any desired quality as well as quantity can be produced in any iron-work. For casting the now so much wanted heavy ordnance, steel plates, bars, or other protection for ships, turrets, forts, &c., for large shaftin gs, steam-cylinders, tires, railroad wheels and rails in short, for all such castings where large and homogeneous masses of steel can be used to advantage-my process presents none of the great difficulties that now enshroud the manufacture of cast-steel for the above-named purposes. Another and not the least important advantage consists in the most perfect control of the process, thereby conditioning the desired quality offthe steel-an advantage presented neither by the Bessemer nor any other process known attached drawings is shown a large reservoir made ofthe best fire-proof material, constructed in the shape of a box or otherwise, having, in

'order to strengthen it, four or more supports,

and the whole placed on four or more fire-proof pillars. Into the reservoir I introduce at rst good wrought-iron in small pieces and expose the same to a welding-heat. I then throw on this hightly-heated iron a proportioned quantity of oxides of iron alone or mixed with oxide of man ganese. (The percentage of carbon in the following admixture of cast-iron conditions the quantity of the oxides|to be added), Immediately after the required quantityof cast-iron taken directly from the blast, cupola, or other smelting-furnace is poured into the reservoir on the highly-heated wrought-iron and oxides, leaving the whole mass exposed between one or two hours, or more or less, according to the size of the wrought iron pieces employed. After the whole mass has acquired the desired texture, which can be ascertained by a sample taken from the reservoir, the steel is run out through a tap-hole and allowed to ow into the molds or forms. This reservoir can also be used as receptacle to receive the contents of smaller crucibles in which steel has been before melted, so as to allow the formation of peculiar mixtures and facilitate the casting of larger pieces. This process can also be carried on in such furnaces-as, for instance, G. W. Swetts patent smelting-furnace, where the wrought-iron can be heated in the lower reservoir while cast-iron is melted in the upper one and made to flow on the iron in the former.

b. For the manafaotare of finer qualit-ies of steel for gan-barrels, knives, files, razors, dto.- I prefer the use of ordinary crucibles. (Those that I make without addition oftplumbago I consider the best.) I arrange the same in the neighborhood of a cupola or other melting-furnace in the required number and in such manner that they are accessible and can easily be brought to a high temperature. A plan of such an arrangement is represented in Fig. II. The crucibles are rst filled with the required quantity ot' thin iron scraps-as, forinstance, sheetiron strips, wire, nails, Sto-and heated up to a White welding-heat. Pure oxide of ironfor instance, such as has been obtained by precipitation from sulphate ot' iron-is then added, and immediately afterward meltedcastiron of the best quality is allowed to flow into the crucibles and on thehighly-heted wroughtiron. The erucibles are then covered and left for an hour, or more or less, exposed to the high temperature of the furnace. According to the qualities of steel desired, I add such materials as influence the same in connection with the oxide ot' iron. For instance, if soft steel for gun-barrels is required, I increase the quantity .tical knowledge will give the direction for the proportions to be employed.

WhatIclaim, therefore, as my invention, and desire to secu/re by Letters Patent, is The method of converting wrought and cast iron into steel in the manner and for the purposes above specified.

WILLIA IW GERHARDT.

Witnesses:

A. I). FLEURY, lnvrNe HAYNES. 

